Time and monetary expenses for business trips and the like may be reduced by conducting a video conference. The video conference may be effected by transmitting and receiving video data and audio data between plural transmission terminals by using a transmission system based on a communication network, such as the Internet. Due to improvements in broadband technology in recent years, it is now possible to transmit or receive high-quality image and audio data. As a result, participants of a video conference can not only monitor the situation on the other end of the communication line but also communicate verbally with one another with an improved level of understanding.
During the video conference, the conference participants may discuss material displayed on the screen of a computer separate from the transmission terminal on one end of the transmission line. In such a case, a participant on the one end may wish to transmit the data of the displayed material (which may be referred to as “display data”) to another participant across the communication network so that they can share the same material, in addition to transmitting audio data or video data from one party to the other.
U.S. Pat. No. 6,760,749 B1 discusses a technology whereby the display data of a material, which is referred to as “presentation content” in the related art, is transmitted together with the audio and video data to a distributing apparatus during a telephone conference via a network. The distributing apparatus then distributes the data or other information to transmission terminals. In this way, the video conference participants can refer to the same material while listening to or looking at each other during the video conference.
However, in the above related art, when the material (presentation content) is managed in a computer other than the transmission terminal from which the video or audio data is transmitted during the conference, the computer needs to be placed under the management of a transmission managing system. As a result, the processing load of the transmission managing system increases.